• dict.first_key = lambda self: next(iter(self))
  • dict.first_val = lambda self: next(iter(self.values()))
  • dict.first_item = lambda self: next(iter(self.items()))
  • dict.last_key = lambda self: next(reversed(self))
  • dict.last_val = lambda self: next(reversed(self.values()))
  • dict.last_item = lambda self: next(reversed(self.items()))
But I think I like a lot more the idea of adding general ways of doing these things to itertools.

Except many iterables don’t have a last item. And many more can’t give you the last item efficiently.

-CHB


On 5 Oct 2021, at 05:30, Christopher Barker <pythonchb@gmail.com> wrote:


On Mon, Oct 4, 2021 at 5:46 PM Erik Demaine <edemaine@mit.edu> wrote:
Have folks thought about allowing indexing dictionary views as in the
following code, where d is a dict object?

d.keys()[0]
d.keys()[-1]
d.values()[0]
d.values()[-1]
d.items()[0]
d.items()[-1]  # item that would be returned by d.popitem()

since dicts were made order-preserving, indexing the keys, items, etc does make some sense.


> I've also often wanted to get an arbitrary item/key from a dictionary, and

This is indeed one of the use cases identified.

I found some related discussion in
https://mail.python.org/archives/list/python-ideas@python.org/thread/QVTGZD6USSC34D4IJG76UPKZRXBBB4MM/
but not this exact idea.

That's a pretty different idea but this exact idea has been discussed on this list relatively recently. I still like it, but there wan't much general support.

I'll leave it exercise for the read to find that thead, but it is there, and I suggest you look for it if you want to further pursue this idea.

-CHB


--
Christopher Barker, PhD (Chris)

Python Language Consulting
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  - Scientific Software Development
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--
Christopher Barker, PhD (Chris)

Python Language Consulting
  - Teaching
  - Scientific Software Development
  - Desktop GUI and Web Development
  - wxPython, numpy, scipy, Cython